Credit pulse generating system for vending machines

ABSTRACT

A system is provided in which the momentum of a moving credit indicator, such as a coin or token, is directed against a mechanically deformable converter, such as a piezoelectric crystal, to produce a signal pulse utilized in determining credit to be granted a vending machine customer. A separate compartment with an associated piezoelectric crystal is provided for each type of credit indicator deposited in the vending machine. The individual components of the system in each compartment are easily assembled and at least a number thereof are maintained in position without soldering or other fastening procedures until the compartments are assembled into a composite unit.

Johnson Dec.4,1973

[ CREDIT PULSE GENERATING SYSTEM FOR VENDING MACHINES [75] Inventor:Kurt Theodore Johnson, Palatine,

Ill.

[73] Assignee: The Seeburg Corporation oi Delaware, Chicago, Ill.

[22] Filed: Feb. 3, I972 [21] Appl. No.: 223,147

OTHER PUBLICATIONS Castrodale; Piezoelectric Punch Checking Arrangement,IBM Technical Bulletin, Vol. 12, No. 9, 2-1970.

Sharp; Piezo-electric Crystal Keyboard", IBM Technical DisclosureBulletin, Vol. 5, No. 10, 3-1963.

Primary Examiner-Robert B. Reeves Assistant Examiner-David A. ScherbelAttorney-.Ronald L. Engel et a1.

[57 4 ABSTRACT A system is provided in which the momentum of a movingcredit indicator, such as a coin or token, is directed against amechanically deformable converter, such as a piezoelectric crystal, toproduce a signal pulse utilized in determining credit to be granted avending machine customer. A separate compartment with an associatedpiezoelectric crystal is provided for each type of credit indicatordeposited in the vending machine. The individual components of thesystem in each compartment are easily assembled and at least a numberthereof are maintained in position without soldering or other fasteningprocedures until the compartments are assembled into a composite unit.

13 Claims, 20 Drawing Figures PATENTED DEC 4 I975 SHEET U 0F 4BACKGROUND OF THE INVENTION 1. Field of the Invention This inventionrelates generally to a system for producing an electrical signal inresponse to the motion of an inanimate object, and, more specifically,this invention relates to the use of a piezoelectric crystal to convertthe motion of a coin or other credit indicator into an electrical signalwithout the necessity of any moving parts and hence replace conventionalcoin switches.

2. Description of the Prior Art It is customary in the vending machinefield to validate deposited credit indicators, such as coins or tokens,and then direct these credit indicators to coin switches to register theappropriate credit. These coin switches normally include a pivoted leveror paddle which is struck by the falling coin. The paddle bears againsta contact bearing switchblade at the end opposite that from the end ofthe paddle struck by the falling coin; Thus, striking of the paddle bythe falling coin pivots the paddle and causes the movable contact on theswitchblade to engage a contact on another switchblade and hence closean electrical circuit to produce the coin pulse.

These coin switches are extremely difficult to adjust accurately inorder to give the proper pulses. For example, if the tension of thefirst switchblade is too great, the falling coin might rebound after theinitial impact and thus cause more than one closure of the switch, whichis generally known as coin or paddle bounce. On the other hand, if thetension is too small, the engagement of the contacts might be so'forceable as to cause the contacts to strike and separate, thus causingcontact bounce." These malfunctions may result in more credit beingawarded than is called for by the credit indicator. Coin or paddlebounce and contact bounce might also result from improper adjustment ofthe tension of the second switchblade.

Due to the precision that is required in the adjustment of theseswitches, they are quite fragile and hence are easily damaged bothduring shipment and in operation. If the adjustments are inaccurate,either due to initial setting or subsequent impairment, the coin pulsesmay be too short or too long or otherwise unsuitable due to breaks ordiscontinuities.

Further, the fact that moving parts are utilized, there is always aconsiderable margin of error. For example, a paddle may wobble or stick.The margin of error is magnified and the switches become even moreunreliable as dirt accumulates in the machine. Another disadvantage thatresults from usage is the socalled dirty contacts" that cause conductingproblems, due to the accumulation of nonconducting materials on thecontact surfaces.

SUMMARY OF THE INVENTION The present invention was developed in order topro vide a credit pulse production arrangement in which there would beno moving parts. Briefly, this is accomplished by utilizing amechanically deformable converter, such as a piezoelectric crystal ormagnetostrictive device, against which a falling credit indicator suchas a coin or token impinges. (For ease of reference, the

credit indicator will be hereafter referred to as a coin, but suchreference is not to be viewed as a limitation on the use of the presentinvention, which may be utilized in connection with any type of movingobject such as coins or tokens.) It should be noted that, strictlyspeaking, there is a movement of the converter upon deformation, butthis motion is not of the type that creates the problems of prior artdevices.

In the preferred embodiment disclosed herein, a piezoelectric crystal isutilized. The mechanical deformation of the crystal produces anelectrical signal pulse in accordance with the well-known piezoelectriceffect. It has been found that this pulse has a shape and magnitude thatpermits it to be directly utilized to drive logic circuits (afterappropriate clipping). This eliminates the problems that resulted fromthe useof moving parts and the necessity of fine adjustments that arepresent in prior art coin switches, while at the same time permittingthe removal of much filtering circuitry between the coin switch and thecontrol circuitry of the vending machine.

These results are achieved by having a separate piezoelectric crystalfor each denomination of coin (or token, etc.) that is deposited in thevending machine. Each coin is directed to a compartment in which apiezoelectric crystal representative of that denomination of coin islocated. The directing means include a guide means which direct the cointo impinge upon a strip of flexible conducting material that acts as astriking area for the crystal. (Of course, the striking surface need notbe a flexible strip but'could be a soldered wire, etc.). This flexiblestrip also holds the crystal snugly against a block of conductingmaterial (the anvil), which is rigidly positioned on the other sidethereof. The strip of flexible conducting material and the block ofconducting material also serve as the conductors by which the electricalsignal produced by the crystal is transmitted to appropriate circuitryin the vending machine.

Both the strip of flexible conducting material and the block ofconducting material are mounted on a mounting wall. The block ofconducting material is riveted to the mounting wall. A pair of mountingpins extend from the mounting wall on opposite sides of thepiezoelectric crystal. Hence, mounting means for the crystal areprovided on four sides by the mounting pins, the strip of flexibleconducting material and the block of conducting material. Thepositioning of the mounting pins and the structure of the block ofconducting material is Various attempts have been made to alleviate someof these difficulties, such as providing better and more easily operableadjusting arrangements. In other cases, some of the disadvantages havebeen overcome by electromagnetically inducing pulses in order tominimize the contact problems. However, even these improvements over thebasic coin switches presently utilized have involved moving parts and atleast some of the attendant difficulties.

such that a coin striking the strip of flexible conducting material andcausing the piezoelectric crystal to produce a signal is directed awayfrom the strip in an angular fashion, so that the coin does not reboundand again land on the flexible strip to produce a second pulse.

Supporting pins extend from the mounting wall to support another blockof conducting material which is engaged by the other end of the strip offlexible conducting material. The flexible strip also bears against theend of a guide member and a positioning pin extending from the mountingwall that cause the strip to be distorted and bear against the crystaland the second block with a tension force. The force exerted by thestrip of flexible conducting material on the piezoelectric crystal andthe second block of conducting material causes these elements to bemaintained in position without any additional securing or fasteningdevices, such as solder or mounting screws.

- The other surface of each mounting wall (except for the mounting wallat one end of the assembly) faces the mounting surface of a mountingwall in an adjacent compartment. Thus, the compartments are formed byplacing two appropriate mounting walls in conjunction. After assembly ofeach of the compartments, end walls are located at each end of thestacked compartments and the whole assembly is permanently secured bytwo mounting bolts.

Therefore, it is the primary object of this invention to provide adevice for producing credit pulses in a vending machine that does notutilize any moving parts.

Another object of this invention is to provide a system for producingcredit pulses in a vending machine that does not require any switchadjustments.

It is a further object of this invention to provide a credit pulseproducing system in a vending machine that generates credit pulseswithout the discontinuities exhibited by prior art devices.

Yet another object of this invention is to provide a credit pulseproducing system for vending machines that permits the elimination ofexpensive filter circuitry needed with prior art devices.

Still a further object of this invention is to provide a coin-pulseproducing system that may be easily assembled and which may bemaintained with'a minimum of fastening devices.

Still another object of this invention is to provide a coin pulseproducing system in which some of the components of the individual coincompartments are maintained in place during assembly without thenecessity of any extra fastening devices.

These and other objects, advantages, and features of this invention willhereinafter appear, and for purposes of illustration, but not oflimitation, exemplary embodiments of the subject invention are shown inthe appended drawing.

BRIEF DESCRIPTION OF THE DRAWING FIG. 1 is a front elevational view ofthe credit pulse generating system of the present invention shownconnected to the coin chute of a vending machine.

FIG. 2 is a right side view of the device illustrated in FIG. 1.

FIG. 3 is a top plan view of the credit pulse generating systemillustrated in FIG. I.

FIG. 4 is a partially exploded view illustrating the components of asingle coin compartment in the credit I FIG. 9 is a plan view of'themounting surface of a mounting wall for another compartment of thecredit pulse generating system of the present invention.

FIG. 10 is a plan view of the other surface of the mounting wallillustrated in FIG. 9.

FIG. 11 is a plan view of the mounting surface of the mounting wall forstill another coin compartment of the credit pulse generating system ofthe present invention.

FIG. 12 is a plan view of the other surface of the mounting wallillustrated in FIG. 11.

FIG. 13 is a plan view of the mounting surface of the mounting wall foryet another coin compartment in the credit pulse generating system ofthe present invention.

FIG. 14 is a plan view of the opposite surface of the mounting wallshown in FIG. 13.

FIG. 15 is a schematic illustration of a typical coin pulse produced byprior art coin switches.

FIG. 16 is a schematic illustration of a pulse produced by the creditpulse generating system of the present invention.

FIG. 17 is an enlarged view of the converter portion of the credit pulsegenerating system of the present invention.

FIG. 18 is another embodiment of the present invention.

FIG. 19 is another embodiment of the present invention.

FIG. 20 is another embodiment of the present invention.

DETAILED DESCRIPTION OF THE PREFERRED. EMBODIMENT herein utilizes coins,reference to the credit indicators deposited in a vending machine willbe limited to coins for purposes of this description of the preferredembodiment.

The credit pulse generating system encapsulated unit 20 is bounded by anend wall 24 (FIGS. 5 and 6) and mounted on a projecting plate 26 fromcoin chute 22. Individual coin compartments are formed by mounting walls28, 30, 32 and 34, in conjunction with end wall 24, in this particularembodiment. It should be recognized, of course, that the use of fourcoin compartments is merely illustrative of this particular embodimentand that as many coin or credit indicator compartments as required for aparticular situation may be employed. Y

The individual mounting walls 28, 30, 32 and 34 are illustrated in FIGS.7 & 8, 9 & 10, 11 & l2, and 1 3 & 14, respectively. Each 'of themounting walls has thereon the components shown in the exploded view ofFIG. 4. A pair of mounting pins 36 and 38 extend from the mounting wallto provide a space therebetween for a piezoelectric crystal 40, which isthe mechanically deformable converter utilized in this preferredembodiment. Of course, another type of mechanically deformableconverter, such as a magnetostrictive device, could be utilized also.Pins 36 and 38 are placed such that a line through the centers thereofwould be at an angle to the horizontal. Piezoelectric crystal 40 may beplaced to produce either positive-going or negativegoing signals. Onesurface may be coated with a gold conductor while the opposite surfaceis coated with a silver conductor in order to readily determine theappropriate positioning in order to obtain the desired polarity. 1

The piezoelectric crystal 40 rests on a block of conducting material 42.Block 42 may be formed of any suitable conducting material, such asbrass. A sloped surface 44 is provided on block 42 at an angle to matchthe angle of pins 36 and 38. At the other end of block 42 there islocated a terminal 46, which extends beyond casing 20.

A strip of flexible conducting material 48 is positioned above thepiezoelectric crystal 40 and pins 36 and 38. The non-horizontalrelationships of pins 36 and 38, and the corresponding slope of portion44 ofblock 42, is provided in order to have the top surface of crystal40 parallel to strip 48. Strip 48 is at an angle to the horizontal toinsure that after a coin strikes the piezoelectric crystal it isdeflected away from the crystal so as to prevent any coin bounce, orrepetitive actuations.

Flexible strip 48 may be any type of spring metal, such as phosphorbronze. The strip of flexible material 48 bears against the crystal 40through a dimple 49 (FIG. 17) and forces it against sloped portion 44 ofblock 42, which provides a rigid support or anvil. Flexible strip 48provides a striking surface against which the coin impinges to compressthe crystal 40, and the dimple 49 concentrates the pressure at a givenpoint. The coin is directed against flexible strip 48 by a guide member50, an end 52 of which serves to support and position the strip 48. End52 of guide member 50 and a positioning pin 54, which extends from themounting wall, position and distort strip 48. Strip 48 also has anextended end portion 56 transverse to the length of strip 48. Endportion 56 engages a groove 58 in a second block of conducting material60. The block 60 has an extending terminal 62 which also protrudesbeyond casing 20. Block 60 is mounted on supporting pins 64 and 66,which extend from the mounting wall. Block 42 is mounted on the mountingwall by rivets 68 and 70.

When the components are being assembled on the mounting wall, block 42is riveted in place and .block is placed on its supporting pins 64 and66. Flexible strip 48 is then forced into position so that it engagesblocks 60, positioning pin 54, end 52 of guide member 50andpiezoelectric crystal 40. Piezoelectric crystal 40 may be insertedbetween mounting pins 36 and 38 either before or after insertion of theflexible strip 48, although it is normally preferable to do ,it afterthe strip is in position to minimize the possibility of damage to thecrystal. As it is necessary to deform strip 48 in order to fit it in theallowed place, it is tensed and serves to retain all the components inplace during assembly of the unit. After all the components have beenmounted on each of the mounting walls, the individual mounting walls arejoined together with end wall 24. Spacers 72, 74, 76 and 78 formed onmounting walls 28, 30, 32 and 34, respectively, position the tops of themounting walls apart from each other in order to form individual coincompartments 73, 75, 77 and 79. A spacer 80 separates plate 26 frommounting wall 34. In asimilar fashion, the bottom portions of themounting walls and end wall 24 are separated by spacers 82, 84, 86, 88,with spacer separating mounting wall 34 from plate 26.

Each of the spacers has a projecting portion that mates with acorresponding bore on the opposing wall to maintain all the walls as acomposite unit until the structure is permanently bound together bybolts 92 and 94, with their respective nuts 96 and 98. These bolts passthrough an opening provided in the spacers 72, 74, 76, 78, 80, 82, 84,86, 88 and 90 and their corresponding projections.

Referring now to FIGS. 5-14, the structure of end wall 24 and theindividual mounting walls may be seen. FIG. 5 illustrates the outer sideof end wall 24 and the openings 100 and 102 through which bolts 92 and94 pass,,respectively. FIG. 6 depicts the other side of end wall 24which, along with the surface of mounting wall 28 illustrated in FIG. 7,forms a nickel coin compartment. On this side of end wall 24 bores 104and 106 are formed about openings 100 and 102, respectively. These boresmate with projections 108 and 110, respectively, on mounting wall 28. Asillustrated in FIG. 7, projections 108 and 110 extend from sleeves 82and 72, respectively. An upper end portion 112 of end wall 24 is flaredoutwardly, so that with a corresponding flared end portion 114 onmounting wall 28 a coin receiving slot is formed.

A tab 116 is formed on end wall 24. Correspnding tabs 118, 120, 122 and124 are formed on mounting walls 28, 30, 32 and 34, respectively. Thesetabs are utilized as an indexing device, so that when the individualwalls are placed together it may be seen at a glance whether they havebeen put in the proper relative positions. This is achieved by placingeach of the tabs at a slightly different position, so, as may be seen inFIG. 1, from a side view the tabs would appear as a solid line. If thereis a break in this line, it is immediately obvious that one of themounting walls (or the end wall) has not been placed in the properposition.

In FIG. 7 it may be seen that mounting surface of mounting wall 28 hasbeen provided with an additional guide member 126. Guide member 126serves, along with guide member 50, to direct the coin against theflexible striking surface 48. Guide member 126 has a length such that acoin rebounding from the striking surface 48 will not strike the guidemember 126, which would cause the coin to rebound against the strikingsurface and the piezoelectric crystal, but will permit the coin to passon to, an appropriate coin box.

The other side of mounting wall 28 is illustrated in FIG. 8, which,along with the mounting surface of mounting wall 30 illustrated in FIG.9, forms the quarter coin compartment of this embodiment of theinvention. A series of three ridges 128, 130 and 132 extend from thisside of mounting wall 28. These ridges determine the width of thecompartment between the ends of these ridges and mounting wall 30through which the quarters pass. The upper portion 134 of mounting wall28 is flared back toward the nickel compartment, in order to form a coinreceiving slot with a flared upper portion 136 of mounting wall 30.Bores 138 and 140 mate with projections 142 and 144, respectively, onmounting wall 30 to position mounting walls 28 and 30 with respect toeach other. A guide member 146, similar to guide member 126 but adaptedto the larger size ot'the quarter coin, is formed on mounting wall 30.

The other side of mounting-wall 30 (FIG. 10) cooperates with themounting surface of mounting wall 32 to form the dime coin compartment.Ridges 148 and 150 define the size of the dime compartment. Upperportions 152 and 154 of ridges 148 and 150, respectively,

are flared toward the quarter compartment to form a coin receiving slotfor the dimes in conjunction with a similarly flared portion 156 at thetop of mounting wall 32. Bores 158 and 160 mate with projections 162 and164, respectively, on mounting wall 32 to position and maintain mountingwalls 30 and 32 with respect to each other.

Mounting surfaces of mounting walls 32 and 34, as illustrated in FIGS.11 and 13, are essentially the same as the mounting surfaces of themounting walls illustrated in FIGS. 7 and 9. Mounting wall 32 has aguide member 166 and mounting wall 34 has a guide member 168 which areadapted to the size of the respective dime and half dollar coins withwhich these mounting walls are associated. The other side 'of mountingwall 32 has three extended ridges 170, 172 and 174 which have respectiveflared top portions 176, 178 and 180 which, along with flared portion182 on mounting wall 34, form a coin receiving slot for the halfdollars.

FIGS. and 16 illustrate comparative pulses produced by a conventionalcoin switch and the pulse generating system of the present invention. Inthe example of a coin switch pulse illustrated in FIG. 15, a first break184 occurs as the result of contact bounce produced when the contactsare caused to engage a coin striking the actuating paddle. Breaks 186,188, 1 90, 192 and 194 occur as a result of dirty contacts orinsufficient contact force (which could result from an improperadjustment of the switchblades). Break 196 occurs from paddle bounceresulting from too great a tension in one of the switchblades. It isapparent that a pulse of this nature would have to be carefully filteredin order to preclude the unwarrented granting of credit to a customerand to distinguish one coin pulse from another. Of course, not all coinswitch pulses are this imperfect, but even one break creates theproblem.

On the other hand, the pulse produced by the system of th presentinvention, as illustrated in FIG. 16, is a single clean pulse that maybe clipped at any desired level, such as at the point shown by line 200,to produce a single pulse that requires no filtering and which may befed directly to controlling logic circuitry. Obviously, the prior artdisadvantages have been obviated to a considerable degree.

Although there are no moving parts, dirt accumulation in the systemcould still create some problems by creating low-leakage resistancepaths. With the-unit produced pursuant to the present invention it isnot neessary, however, to dismantle the assembly for cleaning. Thesystem may be easily cleaned by merly sloshing the entire unit in aproper detergent solution and shaking out any excess detergent.

It should be recognized that forces other than the compression forceused in the preferred embodiment may be utilized to deform the crystaland produce electrical signal. For example, a bending force or a torsionforce could be utilized to deform the crystal.

FIG. 18 illustrates an arrangement in which a bending force is usedinstead of a compression force. In this embodiment, a falling coin 202strikes a paddle 204. Rotation of paddle 204 under the force of the coincauses actuating rod 206 to follow the motion of end 208 of paddle 204as a result of the force of spring 210.

to assume the dotted line position shown in FIG.'18. After the coin 202passes the end of paddle 204, return spring 212 returns the paddle 204,actuating rod 206 and crystal actuator 214 to the solid line positionsshown in FIG. 18. The motion of crystal actuator 214 causes the crystalunit 216 to produce an output signal by bending and hence deformingcrystal 218. The signal is picked up by conducting plates 220 and 222and conveyed to the vending machine system by leads 224 and 226.

This alternative embodiment still has the problems inherent in a movingpaddle, but is does eliminate the need for accurate adjustment ofswitchblades and an external power source.

In FIG. 19 another embodiment is shown in which a coin 228 strikes animpact block 230. The impact block moves a rod 232 to cause a plunger234 to impact on crystal 236. The resultant deformation of crystal 236produces an electrical signal on leads 238 and 240.

The embodiment shown in FIG. 20 is a generalized version of thepreferred embodiment described herein.

- A coin 242 hits a striking pad 244 to distort crystal 246 Spring 210is relatively weak in comparison to the return spring 212. As the coin202 rotates the pedal 204, the actuating rod 206 causes the crystalactuating 214 and produce an electrical signal on leads 248 and 250.Both the FIG. 19 and FIG. 20 embodiments, of course, utilize acompression force. I

It should be understood that various modifications, changes, andvariations may be made in't'he arrangements, operations, and details ofconstruction of the elements disclosed herein without departing from thespirit and scope of this invention.

I claim:

l. A credit pulse generating system-for a vending machine comprising:

a plurality of mechanically deformable converters,

each of said deformable converters representing a particular creditindicator;

mounting means supporting each of said deformable converters in a givenposition, said mounting means comprising: 1

a mounting wall for each type of credit indicator;

a pair of restraining devices on each of said mounting walls, thedeformable converter for that credit indicator located therebetween;

a plurality of blocks of conducting material, each of said blocksextending across an associated pair of said restraining devices on oneside thereof; and

a plurality of strips of flexible conducting material, each of saidstrips extending across an associated pair of said restraining deviceson the other side thereof to retain the corresponding deformableconverter between said restraining devices and against the associatedblock of conducting material and to provide said striking surface fordeposited credit indicators;

directing means causing each credit indicator deposited in the vendingmachine to stress the deformable converter representing that particularcredit indicator, said stress of each of said deformable convertersbeing a compressive force occasioned by the associated credit indicatorimpinging upon a striking surface to compress that deformable con-.verter; and electrical means for detecting and transmitting signalsgenerated by distortion of said mechanically deformable converters uponstress thereof from transfer of kinetic energy from the associatedcredit indicators thereto.

2. A system as claimed in claim 1 wherein said mechanically deformableconverters are piezoelectric crystals.

3. A system as claimed in claim 1 wherein said restraining devices aremounting pins.

4. A system as claimed in claim 1 wherein each of said strips offlexible conducting material is positioned at an angle to the line ofmotion of said credit indicators in order to prevent said creditindicators from striking said deformable converters more than once.

5. A system as claimed in claim 1 and further comprising a projectionformed on each .of said strips of flexible conducting material to engagethe corresponding deformable converter.

6. A system as claimed in claim 1 wherein said electrical means comprisesaid blocks of conducting material and said strips of flexibleconducting material.

7. A system as claimed in claim 1 and furthercomprising:

a positioning projection for each of said strips of flexible conductingmaterial; and

a second plurality of blocks of conducting material,

each of said blocks having a groove formed therein. 8. A system asclaimed in claim 7 wherein: each of said strips of flexible conductingmaterial has a transverse projection formed on one end thereof; and eachof said directing means comprises a guide member having one end thereoflocated in proximity to said positioning projection,

whereby forcing said strip of flexible conducting material between saidpositioningprojection and said end of said guide member distorts saidstrip, causing said transverse projection thereof to engage said grooveof an associated one of said second plurality of blocks of conductingmaterial and causing the other end thereof to forcibly engage theassociated deformable converter.

9. A system as claimed in claim 8 and further comprising a terminallocated on each block of conducting material, whereby the electricalsignal produced by a credit indicator striking a deformable converterappears between terminals on an associated one of said plurality ofblocks of conducting material and on an associated one of said secondpluralityof blocks of conducting material.

10 10. A credit pulse generating system for a vending machinecomprising:

an end wall and a plurality of mounting walls, said walls being placedin proximity to form a plurality of compartments therebetween, each typeof credit indicator deposited in the vending machine having a separatecompartment representative thereof;

each of said compartments comprising:

a pair of mounting members on said mounting wall;

a first block of conducting material rigidly mounted on saidmounting'wall, said first block being located beneath and extendingacross said pair of mounting members;

. a mechanically deformable converter positioned between said pair ofmounting members and on top of said first block of conducting material;

a strip of yieldable conducting material having a portion at one endextending transversely to the length of said strip;

a second block of conducting material mounted on supporting pinsprotruding from said mounting wall and having a groove therein adaptedto receive said portion of said flexible strip;

directing means including a pair of guide members for directing adeposited credit indicator toward said deformable converter;

a positioning projection, the end of one of said guide members beinglocated such that when said flexible strip is forced between saidpositioning projection and said one guide member said strip is distortedwith said portion thereof forced into said groove in said second blockand the other end thereof forced against said deformable converter; and

a terminal connected to each of said first block and said second blockto detect an electrical signal produced by a credit indicator strikingsaid flexible strip immediately above said deformable converter.

11. A system as claimed in claim 11 and further com-.

formable converter is a piezoelectric crystal.

1. A credit pulse generating system for a vending machine comprising: aplurality of mechanically deformable converters, each of said deformableconverters representing a particular credit indicator; mounting meanssupporting each of said deformable converters in a given position, saidmounting means comprising: a mounting wall for each type of creditindicator; a pair of restraining devices on each of said mounting walls,the deformable converter for that credit indicator located therebetween;a plurality of blocks of conducting material, each of said blocksextending across an associated pair of said restraining devices on oneside thereof; and a plurality of strips of flexible conducting material,each of said strips extending across an associated pair of saidrestraining devices on the other side thereof to retain thecorresponding deformable converter between said restraining devices andagainst the associated block of conducting material and to provide saidstriking surface for deposited credit indicators; direCting meanscausing each credit indicator deposited in the vending machine to stressthe deformable converter representing that particular credit indicator,said stress of each of said deformable converters being a compressiveforce occasioned by the associated credit indicator impinging upon astriking surface to compress that deformable converter; and electricalmeans for detecting and transmitting signals generated by distortion ofsaid mechanically deformable converters upon stress thereof fromtransfer of kinetic energy from the associated credit indicatorsthereto.
 2. A system as claimed in claim 1 wherein said mechanicallydeformable converters are piezoelectric crystals.
 3. A system as claimedin claim 1 wherein said restraining devices are mounting pins.
 4. Asystem as claimed in claim 1 wherein each of said strips of flexibleconducting material is positioned at an angle to the line of motion ofsaid credit indicators in order to prevent said credit indicators fromstriking said deformable converters more than once.
 5. A system asclaimed in claim 1 and further comprising a projection formed on each ofsaid strips of flexible conducting material to engage the correspondingdeformable converter.
 6. A system as claimed in claim 1 wherein saidelectrical means comprise said blocks of conducting material and saidstrips of flexible conducting material.
 7. A system as claimed in claim1 and further comprising: a positioning projection for each of saidstrips of flexible conducting material; and a second plurality of blocksof conducting material, each of said blocks having a groove formedtherein.
 8. A system as claimed in claim 7 wherein: each of said stripsof flexible conducting material has a transverse projection formed onone end thereof; and each of said directing means comprises a guidemember having one end thereof located in proximity to said positioningprojection, whereby forcing said strip of flexible conducting materialbetween said positioning projection and said end of said guide memberdistorts said strip, causing said transverse projection thereof toengage said groove of an associated one of said second plurality ofblocks of conducting material and causing the other end thereof toforcibly engage the associated deformable converter.
 9. A system asclaimed in claim 8 and further comprising a terminal located on eachblock of conducting material, whereby the electrical signal produced bya credit indicator striking a deformable converter appears betweenterminals on an associated one of said plurality of blocks of conductingmaterial and on an associated one of said second plurality of blocks ofconducting material.
 10. A credit pulse generating system for a vendingmachine comprising: an end wall and a plurality of mounting walls, saidwalls being placed in proximity to form a plurality of compartmentstherebetween, each type of credit indicator deposited in the vendingmachine having a separate compartment representative thereof; each ofsaid compartments comprising: a pair of mounting members on saidmounting wall; a first block of conducting material rigidly mounted onsaid mounting wall, said first block being located beneath and extendingacross said pair of mounting members; a mechanically deformableconverter positioned between said pair of mounting members and on top ofsaid first block of conducting material; a strip of yieldable conductingmaterial having a portion at one end extending transversely to thelength of said strip; a second block of conducting material mounted onsupporting pins protruding from said mounting wall and having a groovetherein adapted to receive said portion of said flexible strip;directing means including a pair of guide members for directing adeposited credit indicator toward said deformable converter; apositioning projection, the end of one of said guide members beinglocated such that when said flexiblE strip is forced between saidpositioning projection and said one guide member said strip is distortedwith said portion thereof forced into said groove in said second blockand the other end thereof forced against said deformable converter; anda terminal connected to each of said first block and said second blockto detect an electrical signal produced by a credit indicator strikingsaid flexible strip immediately above said deformable converter.
 11. Asystem as claimed in claim 11 and further comprising indexing tabslocated on each of said walls to permit verification that said walls areplaced in the proper relative positions.
 12. A system as claimed inclaim 11 wherein said credit indicators are coins.
 13. A system asclaimed in claim 11 wherein said deformable converter is a piezoelectriccrystal.